CN117247137A

CN117247137A - Aeration system for in-situ ecological elimination of endogenous pollution of water body

Info

Publication number: CN117247137A
Application number: CN202311042909.9A
Authority: CN
Inventors: 韩乐; 姚婧梅; 于雪松; 谭秋君; 梁梓豪
Original assignee: Chongqing University
Current assignee: Chongqing University
Priority date: 2023-01-10
Filing date: 2023-01-10
Publication date: 2023-12-19
Anticipated expiration: 2043-01-10
Also published as: CN116177722A; CN117247137B; CN116177722B

Abstract

The invention relates to an aeration system for in-situ ecological elimination of endogenous pollution of a water body, which comprises an aeration pipe, wherein the aeration pipe comprises an aeration cavity and a gas channel capable of releasing gas to the root of a hollow fiber membrane unit, and the gas channel and the aeration cavity work in a switchable manner. When the aeration chamber is switched for operation, the aeration pipe can be used for aeration only; when the gas channel is switched for working, the aeration pipe can only be used for blowing the root part of the hollow fiber membrane bundle exposed outside the installation part of the aeration pipe, so that the shaking of the root part of the hollow fiber membrane bundle is enhanced, the common phenomena that root membrane wires are too dense and easy to accumulate mud due to the pursuit of high filling density of the traditional hollow fiber membrane module are avoided, the effective filtering area and the filtering uniformity of the hollow fiber membrane wires in the water treatment process are maintained, and the service life of the whole bundle of membrane wires can be effectively prevented from being shortened due to the rapid development and spreading of membrane root membrane pollution.

Description

Aeration system for in-situ ecological elimination of endogenous pollution of water body

Filing and applying for separate cases

The application is a divisional application, the original application number is 202310031348.6, the application date is 2023, 1 month and 10 days, and the invention is named as a coupling system and a coupling method for in-situ ecological elimination of endogenous pollution of a water body.

Technical Field

The invention relates to the technical field of water body endogenous pollution treatment, in particular to an aeration system for in-situ ecological elimination of water body endogenous pollution.

The invention also relates to a coupling system for in-situ ecological elimination of endogenous pollution of a water body, which comprises a benthonic animal enclosure and an aeration membrane bioreactor, wherein the benthonic animal enclosure is partially embedded in a water body substrate, benthonic animals capable of enabling benthonic pollutants in the benthonic animal enclosure to be released into an overlying water layer of the water body by means of self-disturbance capability are arranged in the benthonic animal enclosure; the aeration membrane bioreactor comprises a gas generating device, an aeration membrane carrier and a biological membrane, wherein the biological membrane is attached to the aeration membrane carrier; the aeration membrane carrier is arranged in an overlying water layer of the water body and corresponds to the benthonic animal enclosure arranged above the aeration membrane carrier in the vertical direction, so that the biological membrane can capture benthonic pollutants released upwards due to benthonic animal disturbance from above; the aeration membrane bioreactor has an oxygen supply to the biofilm through the aeration membrane carrier, the oxygen supply to the biofilm through the aeration membrane carrier including oxygen supplied to the biofilm through the aeration membrane carrier and oxygen permeated into the water body substrate.

The invention also relates to a method for in-situ elimination of the endogenous pollution of the water body, which comprises the following steps: arranging a benthonic animal enclosure at a substrate to be treated for polluted water, and putting benthonic animals capable of releasing substrate pollutants into an overlying water layer of the water body by means of self-interference capability in the benthonic animal enclosure; an aeration membrane carrier is arranged above the zoobenthos enclosure in the vertical direction in an upper water layer of the water body, and a biological membrane is attached to the aeration membrane carrier; the oxygen supply to the biological membrane through the aeration membrane carrier is performed, wherein the oxygen supply to the biological membrane through the aeration membrane carrier comprises the oxygen supplied to the biological membrane through the aeration membrane carrier and the oxygen permeated into the water body substrate.

Background

Whether in natural water bodies such as rivers, lakes, oceans and the like or artificial water bodies such as fish ponds and the like in surrounding reservoirs, the endogenous pollution (such as nitrogen and phosphorus nutrient salts, organic matters and the like) is usually much higher than the water bodies themselves (even more than ten times). Under the interference of fluctuation of environmental biological factors (temperature, water flow and organisms), the diffusion release of endogenous pollution is easy to cause concentrated burst of water pollution.

The black and odorous water body substrate sludge is removed as an effective measure for eliminating the endogenous pollution of the black and odorous water body, and is widely applied to urban sewage treatment. At present, the treatment of the black and odorous substrate sludge mainly comprises the steps of transferring or solidifying endogenous pollutants, wherein the treatment method comprises a physical method (such as substrate sludge dredging and artificial aeration), a chemical method (such as flocculant adding) and a biological method (such as aquatic plant planting and microbial agent adding). One of the most widely used measures is to directly remove the sediment of the contaminated part by sediment dredging (dredging). The dredging effect is quick, the total pollutant amount is reduced to a certain extent, but the dredging effect is high in cost and large in engineering amount, has larger damage to lakes and rivers, and can reduce the biomass and diversity of aquatic animals and benthonic animals, so that the substrate condition and micro-habitat of sediment are damaged, and the recovery of the structure and functions of the aquatic ecosystem is seriously hindered.

In addition, measures such as sediment covering or flocculant and phosphorus locking agent addition are also commonly adopted to prevent blockage so as to solidify endogenous pollutants. For the method of adding the phosphorus locking agent, the suspension and desorption of phosphorus can be caused by stormy waves and the disturbance of benthonic animals, so that the effect of the phosphorus locking agent is reduced, and the high-load endogenous pollution can be continuously and slowly released, so that the newly released pollutant is required to be solidified by re-adding the agent after a certain time, the treatment effect is poor, and the cost is high. Curing does not change the total amount of sediment contaminants nor does it allow for complete removal of endogenous contaminants from the ecosystem, which in turn will be re-released once the environment changes.

In addition, bioremediation refers to the absorption, degradation or conversion of contaminants in a deposit by the vital activities and metabolic processes of organisms (mainly including aquatic plants and microorganisms, etc.). However, the aquatic plants absorb pollutants at a slower rate, the effect is not obvious, and the high-pollution black and odorous substrate sludge is difficult to survive in a low-oxygen environment; in contrast, the method of adding the microbial agent is simpler and more convenient to operate, has less influence on the surrounding environment, but the thalli are easy to run off, the maintenance period is short, and the pollutant removal effect is not ideal in the anoxic environment.

Based on the above, the treatment technology of the black and odorous substrate sludge in the prior art cannot truly reduce the endogenous pollution in situ and obtain good water quality purification effect, so that the development of an integration technology capable of truly and ecologically reducing the endogenous pollution and recovering the self-cleaning function of the water body is urgent.

Disclosure of Invention

In view of the above, the invention provides an in-situ ecological elimination method of endogenous pollution and a coupling integrated system thereof, which couple benthonic disturbance with an aeration membrane bioreactor technology, wherein the endogenous pollution is actively released into the upward water through benthonic disturbance, and ecological release removal of the endogenous pollution is realized; the aeration of the membrane aeration device forms a biological membrane on the aeration membrane to carry out in-situ ecological elimination on endogenous pollutants released by biological disturbance, and provides partial oxygen for the water body substrate (sediment and/or sediment) on the other hand, so that the concentration and gradient distribution breadth of dissolved oxygen in the substrate and at the interface of the water body substrate and overlying water are improved, and the ecological micro-habitat at the interface and in the water body substrate is radically improved.

The first aspect of the invention provides a coupling system for in-situ ecological elimination of endogenous pollution of a water body, which comprises a benthonic animal enclosure and an aeration membrane bioreactor, wherein the benthonic animal enclosure is partially embedded in a water body substrate, benthonic animals capable of enabling benthonic pollutants in the benthonic animal enclosure to be released into an overlying water layer of the water body by means of self-interference capability are arranged in the benthonic animal enclosure; the aeration membrane bioreactor comprises a gas generating device, an aeration membrane carrier and a biological membrane, wherein the biological membrane is attached to the aeration membrane carrier; the aeration membrane carrier is arranged in an overlying water layer of the water body along the horizontal direction and is arranged above the aeration membrane carrier corresponding to the benthonic animal enclosure in the vertical direction, so that the biological membrane can capture benthonic pollutants released upwards due to benthonic animal disturbance from above; the aeration membrane bioreactor has an oxygen supply to the biofilm through the aeration membrane carrier, the oxygen supply to the biofilm through the aeration membrane carrier including oxygen supplied to the biofilm through the aeration membrane carrier and oxygen permeated into the water body substrate.

Further, the oxygen supply to the biofilm through the aerated film carrier also includes oxygen dissolved at the water substrate-water interface, such that the concentration of dissolved oxygen at the water substrate-water interface is also improved.

Further, benthonic animals can create a hole corridor in a water body substrate with accumulation of toxic substances (such as excessive nitrogen and phosphorus, organic matters, other toxic and harmful matters and the like) by means of self-disturbance, and oxygen permeated into the water body substrate is the hole corridor created by benthonic animals and permeated into the water body substrate.

The overlying water layer is a water layer that covers the sediment of the water body. Biological perturbation refers to the process of zoo handling and mixing sediment by digging holes, feeding, ventilating, excreting, etc. The aeration membrane bioreactor provides oxygen required for metabolism of the biological membrane attached to the surface layer of the aeration membrane carrier through aeration, wherein the aeration membrane carrier has the dual functions of providing oxygen and serving as the biological membrane carrier. The gas generator is used for continuously supplying gas into the aeration membrane carrier, and the concentration of oxygen in the membrane is higher, so that the oxygen in the membrane can continuously diffuse out of the membrane due to the difference of the selective permeability and the oxygen concentration. The concentration of the pollutants in the water body is higher, a certain concentration difference exists between the pollutants and the outermost layer of the biological film, and the adsorption effect of the biological film on the pollutants can enable the pollutant matrixes with high concentration to be continuously enriched towards the surface layer of the biological film, so that the pollutants are transferred into the biological film, and different concentration distributions are formed at different positions. The microbes selectively form a unique layered structure on the surface of the membrane according to different oxygen gradients outside the membrane, different areas have different functional groups, pollutants in the water body are decomposed into stable substances in the different functional areas through the actions of aerobic oxidation, nitrification, denitrification, aerobic phosphorus absorption and the like, and then the stable substances are discharged into the environment, so that the water body is purified, the microbes also realize self proliferation, and the effect of removing the pollutants is achieved.

In the invention, the in-situ ecological elimination of the endogenous pollution of the water body is realized through the mutual coupling of the benthonic animal disturbance technology and the aeration membrane bioreactor technology. The biological disturbance of benthonic animals can promote pollutants in the substrate to be released into the upward water, the aeration membrane carrier provides an attachment place for microorganisms besides providing oxygen for a system, and the aeration membrane carrier is directly arranged right above the benthonic animal enclosure in the water layer covered on the water body, so that the biological membrane attached to the aeration membrane carrier captures endogenous pollutants released upwards through the biological disturbance. Specifically, under the combined action of benthonic animal disturbance and membrane aeration biological membrane in-situ ecological elimination coupling technology, carbon, nitrogen and phosphorus in a black and odorous system are effectively removed; the biological film attached to the aeration film carrier can absorb nitrogen and phosphorus in a dissolved state, is eliminated by microbial transformation, forms an isolation layer and reduces the release of endogenous nitrogen and phosphorus into a water body.

In addition, in the invention, benthonic animals can accelerate the transfer effect of oxygen in the process of biological disturbance, promote the gradient distribution of dissolved oxygen at the water substrate-water interface and dissolved oxygen in the water substrate, and locally construct anaerobic/anoxic/aerobic interfaces, thereby being beneficial to the growth of substrate deep anaerobic ammonia oxidizing bacteria. In addition, the self disturbance of benthonic animals can create hole galleries in the water body substrate, in the process, not only the muddy water interface area and the consumption of dissolved oxygen in sediment are increased, but also the overlying water is intermittently pumped into the hole galleries, and electron acceptors such as nitrate in the overlying water are brought into the lower layer of the sediment, so that the diffusion distance of the nitrate in the overlying water to an anoxic denitrification area of the bottom layer of the sediment is shortened, and the denitrification reaction is further promoted. In addition, bacteria with a larger quantity than the surface layer of sediment exist in a duct created by disturbance of benthonic animals, and the bacteria contain a large quantity of denitrifying bacteria, so that the system denitrification reaction is better promoted.

Meanwhile, in the above system, the aeration membrane carrier is disposed relative to the water substrate such that oxygen supplied to the biofilm partially permeates into the water substrate (e.g., sediment or sediment) and is supplied to the interface of the water substrate and water. That is, in the present invention, oxygen supplied to the biofilm through the aeration membrane carrier is supplied to the biofilm through the aeration membrane carrier, and also some of the oxygen is supplied to and permeated into the interface of the water body substrate and the water, so that the concentration of dissolved oxygen at the interface and in the water body substrate is increased. The increase in dissolved oxygen concentration promotes NH release of the sediment up to the overlying water ₄ ⁺ -N-direction NO ₂ ^- -N，NO ₃ ^- Conversion of N, which to a certain extent enlarges the concentration difference between the overlying water and the ammonia nitrogen in the deposit, accelerates NH by means of a concentration gradient ₄ ⁺ Release of N, such that NH ₄ ⁺ N is reduced by the use of. After the sewage passes through the biomembrane layered structure in the reactor, synchronous Nitrification and Denitrification (SND) can be performed, so that NH ₄ ⁺ Conversion of N to NO ₂ ^- -N，NO ₃ ^- After N, the ammonia nitrogen is converted into nitrogen for discharge, and ammonia nitrogen is removed mainly by nitrifying bacteria, so that the ammonia nitrogen removal is enhanced due to the increase of the concentration of dissolved oxygen.

In the invention, under the combined action of benthonic animal disturbance and membrane aeration biological membrane in-situ elimination coupling technology, denitrification is enhanced while the growth of anaerobic ammonia oxidizing bacteria is facilitated.

Further, the aeration membrane carrier comprises a plurality of hollow fiber membrane units, each hollow fiber membrane unit is composed of a plurality of membrane filaments made of polypropylene material and/or polytetrafluoroethylene and/or polyvinylidene fluoride material, and the hollow fiber membrane carrier is formed. In a preferred embodiment, the aeration membrane carrier is made of a dense microporous hollow fiber membrane material with good air permeability, and the membrane is used as a carrier, so that a large surface area can be provided for the growth and propagation of microorganisms in a small space, thereby increasing the density of the microorganisms, and bubble-free aeration can be provided, so that the oxygen mass transfer efficiency is much higher than that of a conventional aeration system, and the oxygen demand can be met, and the energy can be saved. In a preferred embodiment, the aeration membrane carrier of the present invention is a curtain-type hollow fiber membrane module composed of a plurality of hollow fiber membrane units, each hollow fiber membrane unit being composed of a plurality of hollow fiber membrane filaments, the curtain-type hollow fiber membrane module being disposed right above the zoobenthos enclosure in the horizontal direction for capturing ecologically released pollutants.

Further, the gas generating device is a solar aerator which is communicated with an aeration membrane carrier arranged in an overlying water layer of the water body through an air conveying pipe, so that intermittent and low-energy-consumption oxygen supply is realized.

Further, the zoobenthos enclosure is made of waterproof high polymer material, is of rectangular structure, and the upper surface and the lower surface are not sealed.

Further, the benthonic animal is one or more of oligotrichomes, midge larvae, snails, shellfish and nematodes.

Further, the aeration membrane carrier is arranged 5cm to 15cm away from the water body substrate.

Further, in the present application, in order to solve the problem that the root deposit of the hollow fiber membrane used as the carrier for the aeration membrane in the prior art is difficult to be removed, the coupling system of the present invention further provides an improved aeration system including an aeration pipe for mounting the hollow fiber membrane bundle and for aeration, the aeration pipe including a mounting portion for mounting the hollow fiber membrane bundle, an aeration chamber formed after mounting the hollow fiber membrane bundle, and a gas passage capable of receiving a gas and releasing the gas to the root of the hollow fiber membrane bundle, wherein the aeration chamber communicates with the inner cavity of the mounted hollow fiber membrane bundle, the gas passage and the aeration chamber are disposed in a non-communicating manner with each other, and the gas passage and the aeration chamber are operated in a switchable manner. In a specific embodiment, two aeration pipes are arranged corresponding to each hollow fiber membrane unit or each hollow fiber membrane group, the two aeration pipes are arranged corresponding to two ends of the hollow fiber membrane wires, and the end parts of the hollow fiber membrane wires are fixed in the mounting parts of the corresponding aeration pipes. The hollow fiber membrane filaments can be configured to form an air inlet end for one end in air communication with a corresponding aeration tube and a plugged structure at the other end, and in other embodiments can also be configured to form an air inlet structure for both ends in air communication with a corresponding aeration tube.

In the present invention, the bottom of the aeration tube has an approximately circular structure, and the inner cavity thereof is divided into a main gas passage of the gas passage and the aforementioned aeration chamber in the radial direction by an inner partition extending in the length direction of the aeration tube. An adjusting plate with an L-shaped integral structure is arranged at the air inlet of the aeration pipe, the adjusting plate is rotatably arranged at the air inlet of the aeration pipe and has a first working position (initial position) and a second working position, and the adjusting plate can be pushed to move from the first working position to the second working position when the gas pressure exceeds a certain threshold value. At the first working position, the first plate body of the adjusting plate is in abutting fit with the inner partition plate, the second plate body of the adjusting plate seals the inlet of the main air passage of the gas channel, at the moment, the inlet of the aeration chamber is opened, and gas from the gas generating device can only enter the aeration chamber through the inlet port of the aeration pipe; when the adjusting plate is at the second working position, the second plate body of the adjusting plate is in abutting fit with the inner partition plate, the first plate body of the adjusting plate seals the inlet of the aeration chamber, at the moment, the inlet of the main air passage of the gas passage is opened, and gas from the gas generating device can only enter the main air passage of the gas passage through the inlet port of the aeration pipe.

When the L-shaped adjusting plate is in the first working position, the aeration pipe can only be used for aeration, so that gas enters the hollow inner cavity of the hollow fiber membrane bundle, and then oxygen necessary for microbial membranes is supplied and the concentration of dissolved oxygen in the water body substrate is adjusted. When the regulating plate of L shape is in second working position department, the aeration pipe only can be used for exposing the root outside the installation department of aeration pipe to the hollow fiber membrane bundle to the shake of reinforcing hollow fiber membrane bundle root, the universal phenomenon that root membrane silk is too intensive, easy deposition is because of pursuing to pack the density big in current hollow fiber membrane module can be fine avoided, hollow fiber membrane silk filterable effective area and filterable homogeneity of water treatment in-process can remain all the time, and can effectively prevent to shorten whole bundle of membrane silk's life because of the fast development and the spreading of membrane silk root membrane pollution.

In the present invention, the gas passage further comprises a side gas passage provided along a side wall of the aeration tube and gas outlet passages communicating with the side gas passage, each of the gas outlet passages being provided obliquely in such a manner as to enable the gas to be released toward the root of the hollow fiber membrane bundle.

In the invention, the gas channel for sweeping the root of the hollow fiber membrane bundle is integrally arranged on the aeration pipe, so that an additional gas distribution device is not required; and through the switching operation of regulating plate for the aeration pipe can satisfy aeration and to empty fiber membrane bundle root and sweep two mutually independent works.

In addition, in the present invention, the installation part for the hollow fiber membrane bundle provides an installation cavity having a wave shape along the length direction of the aeration pipe, and the installation cavity has wave crests and wave troughs, which makes the hollow fiber membrane bundle form a wave-shaped hollow fiber membrane group adapted to the shape of the installation cavity after being installed to the installation part, thereby greatly improving the effective area of the hollow fiber membrane wire filtration and the uniformity of the filtration within the limited length of the installation part. Wherein, the gas outlet channel of the gas channel is respectively provided with at least one corresponding to each wave crest and each wave trough of the installation cavity so as to ensure the thoroughness and the uniformity of the cleaning of the pollution of the root of the hollow fiber membrane bundle.

In another embodiment of the present invention, an adjustment mechanism is provided that is different from the aforementioned adjustment plate structure. The adjusting mechanism comprises a shell, an air inlet and two air outlet channels, wherein the air inlet is communicated with the gas generating device and is used for receiving gas from the gas generating device; the two air outlet channels are respectively a first air outlet channel and a second air outlet channel, wherein the first air outlet channel is used for being communicated with the inlet of the aeration chamber of the aeration pipe, and the second air outlet channel is used for being communicated with the main air channel of the gas channel of the aeration pipe. The regulating mechanism comprises an air passage switching mechanism arranged in the shell, wherein the air passage switching mechanism comprises an inner shell, a diaphragm, a first stop valve and a second stop valve. Wherein the diaphragm is made of soft material, preferably made of silica gel, has a hemispherical structure and can deform in the opposite direction of the initial state under pressure; a diaphragm is disposed within the interior cavity of the inner housing and divides the interior cavity of the inner housing into a first chamber and a second chamber.

In the adjusting mechanism of the above embodiment, the first stop valve includes a first spring, a first push plate, a first slide rod, and a first stop valve body, the first slide rod penetrates out from the first cavity of the inner shell, the first spring is disposed on the first slide rod inside and outside the first cavity of the inner shell, and the first push plate is fixed on a rod end of the first slide rod located in the first cavity. The first shut-off valve body is fixedly arranged on the rod end of the first sliding rod positioned outside the inner shell and can be used for opening and closing the first air outlet channel. The second stop valve comprises a second spring, a second push plate, a second slide rod and a second stop valve body, the second slide rod penetrates out of a second cavity of the inner shell, the second spring is sleeved on the second slide rod inside and outside the second cavity of the inner shell, and the second push plate is fixed on the rod end of the second slide rod located in the second cavity. The second shut-off valve body is fixedly arranged on the rod end of the second sliding rod positioned outside the inner shell and can be used for opening and closing the second air outlet channel.

In the adjusting mechanism of the above embodiment, the diaphragm has the first working position (initial position) where the diaphragm is in the initial state, which is the semicircular convex state toward the second stop valve, and the second working position where the diaphragm is in contact with the second push plate of the second stop valve and presses the second push plate by virtue of the elastic deformation force of the diaphragm itself, so that the second spring is compressed, the second slide rod extends to the outside of the inner case, and finally the second stop valve body of the second stop valve closes the second gas outlet passage. In the first operating position of the diaphragm, the second outlet channel is closed, at which time the gas entering from the inlet of the self-regulating mechanism can only flow out of the first outlet channel, i.e. at which time the aeration operation of the aeration tube is enabled. At the second working position of the diaphragm, the diaphragm is abutted against the second push plate of the first stop valve, and the first push plate is pressed by means of elastic deformation force of the diaphragm, so that the first spring is compressed, the first sliding rod stretches to the outside of the inner shell, and finally the first stop valve body of the first stop valve closes the first air outlet channel. In the second operating position of the diaphragm, the first gas outlet channel is closed, at which time the gas entering from the gas inlet of the self-regulating mechanism can only flow out from the second gas outlet channel, i.e. at which time the gas blowing operation of the aeration tube for the root of the bundle of hollow fiber membranes is enabled.

The transition of the diaphragm from the first operating position to the second operating position is achieved by means of the air pressure of compressed air. When the air blowing work aiming at the root of the hollow fiber membrane bundle is needed, compressed air can be filled into the second cavity through a compressed air inlet pipe communicated with the second cavity of the inner shell, and when the air pressure in the second cavity reaches a certain threshold value (20-50 KPa), the diaphragm is stressed to bend towards the opposite direction, namely a semicircular convex state towards the first stop valve is formed. When the blowing operation for the root of the hollow fiber membrane bundle needs to be stopped, the supply of the compressed air into the second chamber can be cut off, the diaphragm can be restored to the initial state under the restoring force of the first spring of the first stop valve, namely to the semicircular convex state facing the second stop valve, and at the moment, the diaphragm can force the second stop valve to operate so that the second stop valve body seals the second air outlet channel. In the present invention, the spring force of the first spring of the first shut-off valve is different from the spring force of the second spring of the second shut-off valve, and the spring force of the first spring of the first shut-off valve can force the diaphragm to return to the original state after the supply of the compressed air to the second chamber is interrupted, whereas the spring force of the second spring of the second shut-off valve cannot force the diaphragm to be completely deformed in the direction toward the first shut-off valve.

In the embodiment, in the adjusting mechanism formed by matching the diaphragm and the stop valve, the diaphragm generates deformation from the second stop valve to the first stop valve along with the filling of the compressed air, and the deformation control mode is simple and sensitive, so that the switching between channels can be realized rapidly; the semicircular structure of the valve body of the stop valve can effectively realize complete closure of the corresponding channel when the corresponding channel needs to be closed, and simultaneously, the corresponding channel can be rapidly and sensitively opened when the corresponding channel needs to be opened under the action of the spring.

The second aspect of the invention provides a method for in-situ elimination of endogenous pollution of a water body, comprising the following steps:

arranging a benthonic animal enclosure at a substrate to be treated for polluted water, and putting benthonic animals capable of releasing substrate pollutants into an overlying water layer of the water body by means of self-interference capability in the benthonic animal enclosure;

an aeration membrane carrier is arranged above the zoobenthos enclosure in the vertical direction in an upper water layer of the water body, and a biological membrane is attached to the aeration membrane carrier;

the oxygen supply to the biofilm through the aeration membrane carrier is performed, wherein the oxygen supply to the biofilm through the aeration membrane carrier includes oxygen supplied to the biofilm through the aeration membrane carrier and oxygen permeated into the water body substrate.

Further, the oxygen supply outside through the aeration membrane carrier comprises oxygen dissolved at the water substrate-water interface in addition to the biomembrane attached to the carrier so as to break through the solid-liquid interface related to mud-water, and the solid-liquid-gas three-phase real oxygen enrichment is realized under the assistance of benthonic animals.

In the coupling system and the method for in-situ ecological elimination of the endogenous pollution of the water body, the bottom area of the water body faces to the interface between the bottom mud and the muddy water, and ecological release of substrate pollutants in the enclosure range of the benthonic animals to the upper water layer of the water body is realized through biological disturbance activities such as digging, ingestion and the like of the thrown benthonic animals; and in the upper water layer area of the water body, the in-situ degradation of pollutants ecologically released into the upper water layer through benthonic biological disturbance can be realized based on the aeration membrane carrier arranged above the benthonic animal enclosure and the biological membrane attached to the aeration membrane carrier. That is, in the coupling system of the present invention, endogenous pollution is actively released into the overlying water by benthonic disturbance, ecological release removal of the endogenous pollution is achieved, and then the endogenous pollutant released by biological disturbance is eliminated in situ by a biological membrane attached to an aeration membrane carrier above a benthonic animal enclosure.

The coupling system for in-situ ecological elimination of the endogenous pollution of the water body can play a role in the whole vertical space at the bottom of the water body, and ecological release caused by the disturbance action of benthonic animals can accelerate the flow of endogenous substances in the enclosure range and reduce the storage of endogenous pollutants in the water body substrate; meanwhile, by means of aeration through the aeration membrane carrier, oxygen can be permeated into the water body substrate besides supplying necessary oxygen to the biological membrane, so that the dissolved oxygen concentration of the water body substrate can be improved, the vital activities of the protozoan microorganisms in the substrate are enhanced and guaranteed, and the restoration and reconstruction of the micro-habitat are fundamentally assisted. Unlike traditional film aeration biochemical degradation system, the present invention has partial effect on liquid phase soluble matter in water, breaks through solid-liquid interface of mud-water, expands pollutant degrading area from overlying water to mud-water interface and below, recovers both water-solid phase micro-habitat and realizes solid-liquid-gas three-phase oxygen enrichment.

From the above, the coupling system for in-situ ecological elimination of endogenous pollution of water body disclosed by the invention adopts two pollutant treatment technologies, namely a biological disturbance release technology of benthonic animals and an ecological degradation technology of an aeration membrane bioreactor in a combined manner. In the present invention, these two technologies are capable of achieving not only the respective technical effects but also unexpected synergistic effects therebetween. Specifically, in the invention, oxygen is partially permeated into the water body substrate by virtue of the aeration membrane carrier, so that not only the dissolved oxygen concentration in the water body substrate is improved, but also the life activities of benthonic animals can be enhanced, thereby further promoting the ecological release effect caused by the biological disturbance of benthonic animals. Accordingly, the infiltration of oxygen generated by aeration of the aerated film carrier into the water body substrate can be considerably promoted by means of the biological disturbance behavior of the benthonic animal. That is, by means of biological disturbance of benthonic animals, dissolved oxygen permeated into the water body substrate through aeration of the aeration membrane carrier can be brought into a muddy water interface and a deep layer area of the water body substrate below the muddy water interface, which can greatly excite the life activity of microorganisms in the water body substrate sludge, so that the degradation area of pollutants is further enlarged from the overlying water area to the muddy water interface and below. From this it can be seen that the coupling system of the present invention achieves unexpected technical results compared to prior art solutions using either benthonic disturbance technology or membrane aerated bioreactor technology alone.

The coupling technology provided by the invention consists of units with more ecology, high efficiency and sustainability, and other coupling technologies or only couple microorganisms and plants, so that the conditions of serious hypoxia, difficult adaptation of microorganisms and difficult survival of plants of the heavily polluted water body sediment are not considered; or adopting a symbiotic mode of algae and benthonic animals; or no oxygen environment improvement, no overall process action of release and degradation.

The beneficial effects are that: in the invention, because the gas channel of the aeration pipe and the aeration cavity work in a switchable manner, when the aeration cavity is switched for work, the aeration pipe can only be used for aeration, so that gas enters the hollow cavity of the hollow fiber membrane bundle, and then oxygen necessary for microbial membranes is supplied and the concentration of dissolved oxygen in the water body substrate is regulated; when the gas channel is switched for working, the aeration pipe can only be used for blowing the root part of the hollow fiber membrane bundle exposed outside the installation part of the aeration pipe, so that the shaking of the root part of the hollow fiber membrane bundle is enhanced, the common phenomena that the root membrane wires are too dense and easy to accumulate mud due to the pursuit of high filling density of the traditional hollow fiber membrane module can be well avoided, the effective filtering area and the filtering uniformity of the hollow fiber membrane wires in the water treatment process can be always maintained, and the service life of the whole bundle of membrane wires can be effectively prevented from being shortened due to the rapid development and the spreading of membrane root membrane pollution.

The coupling system for in-situ ecological elimination of water body endogenous pollution of the invention is disclosed in detail below with reference to the embodiments shown in the drawings.

Drawings

Fig. 1 shows the structural arrangement of the coupling system for in-situ ecological elimination of water body endogenous pollution.

Fig. 2 (a) shows the change in the concentration of dissolved oxygen of the overlying water over time.

Fig. 2 (B) shows the depth of dissolved oxygen attack of the deposit at the end of the experiment.

Fig. 3 shows TOC concentration in the overlying water as a function of time.

FIG. 4 shows NH in overlying water ₄ ⁺ -change in N concentration over time.

FIG. 5 shows NO in overlying water ₂ ^- -N and NO ₃ ^- -change in N concentration over time.

Fig. 6 shows the variation of the TN concentration in the overlying water over time.

FIG. 7 shows PO in an overlying water ₄ ^3- Variation of TP concentration with time.

Fig. 8 is a schematic view of the structure of an aeration tube according to the present invention.

Fig. 9 is a schematic view showing a sectional structure of an aeration tube according to the present invention in the direction A-A of fig. 8 after receiving installation of a bundle of hollow fiber membranes.

Fig. 10 is a schematic view of the structure of the adjusting plate in the first working position according to one embodiment of the present invention.

Fig. 11 is a schematic view of the structure of the adjusting plate in the second working position according to one embodiment of the present invention.

Fig. 12 is a schematic view of the structure of the adjustment mechanism in another embodiment of the present invention, wherein the diaphragm is in its first operative position.

Fig. 13 is a schematic view of the structure of the adjustment mechanism in another embodiment of the present invention, wherein the diaphragm is in its second operative position.

Reference numerals

1. Water body substrate

2. Benthonic animal enclosure

3. Aeration film carrier

4. Hole gallery

5. Air delivery pipe

6. Gas generating device

7 stationary or mobile sources (e.g. ground or hull)

8. Aeration pipe

9. Hollow fiber membrane bundle

10. Mounting part

11. Aeration chamber

12. Internal partition

13. Main air passage

14. Adjusting plate

15. First plate body

16. Second plate body

17. Torsion spring

18 19 inclined surfaces

20. Rotating shaft

21. Side air passage

22. Air outlet channel

23. Mounting cavity

24. Shell body

25. Air inlet

26. A first air outlet passage

27. A second air outlet passage

28. Inner shell

29. First cavity

30. Second cavity

31. First spring

32. First push plate

33. First slide bar

34. First stop valve body

35. Second spring

36. Second push plate

37. Second slide bar

38. Second stop valve body

39. Diaphragm membrane

40. Compressed air inlet pipe

41. Vent hole

Detailed Description

The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

It should be noted that, in the embodiments of the present invention, all directional indicators (such as up, down, left, right, front, and rear … …) are merely used to explain the relative positional relationship, movement conditions, and the like between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicators are correspondingly changed.

Furthermore, the description of "first," "second," etc. in this disclosure is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present invention.

Fig. 1 shows the structural arrangement of the coupling system for in-situ ecological elimination of water body endogenous pollution. Referring to fig. 1, the coupling system for in-situ ecological elimination of endogenous pollution of a water body of the present invention comprises a benthonic animal enclosure 2 and an aeration membrane bioreactor, wherein the benthonic animal enclosure 2 is partially embedded in a water body substrate, and benthonic animals capable of releasing benthonic pollutants into an overlying water layer of the water body by means of self-interference capability are arranged in the benthonic animal enclosure 2; the aeration membrane bioreactor comprises a gas generating device, an aeration membrane carrier 3 and a biological membrane, wherein the biological membrane is attached to the aeration membrane carrier 3; the aeration membrane carrier 3 is arranged in an overlying water layer of the water body and is arranged above the corresponding benthonic animal enclosure in the vertical direction, so that the biological membrane can capture substrate pollutants released upwards due to benthonic animal disturbance from above; the aeration membrane bioreactor has an oxygen supply to the biofilm through the aeration membrane carrier, the oxygen supply to the biofilm through the aeration membrane carrier including oxygen supplied to the biofilm through the aeration membrane carrier and oxygen permeated into the water body substrate.

In the above embodiment, the oxygen supply to the biofilm through the aerated film carrier further comprises oxygen dissolved at the water substrate-water interface.

In the above embodiment, the benthonic animal can create the hole corridor 4 in the water body substrate 1 by means of self-disturbance, and the oxygen permeated into the water body substrate is permeated into the water body substrate 1 for the hole corridor created by the benthonic animal.

In the above embodiment, the aeration membrane carrier includes a plurality of hollow fiber membrane units, each of which is composed of a plurality of membrane filaments made of polypropylene and/or polytetrafluoroethylene. The membrane wires have the characteristics of water repellency, ventilation, self-support and high oxygen transmission efficiency, a plurality of membrane wires are combined into one bundle, and the two ends of each bundle of membrane wires are adhered into the hard sealing connectors to keep ventilation.

In the above embodiment, the gas generating means 6 is a solar aerator which communicates with the aeration membrane carrier 3 arranged in the overlying water layer of the water body through the air delivery pipe 5. The air pump is connected with the solar panel and the electricity storage battery system, an external power supply is not needed, and the whole system can be placed on a fixed or movable source (such as the ground or a ship body) 7. The air conveying pipes are multiple rows of PPR pipes, each row of PPR pipes are connected into a ring, the left pipe and the right pipe are connected with multiple bundles of hollow fiber membranes, the head of each bundle of fiber membranes is provided with a hard joint, and the hot melt connection is connected with the PPR pipes.

In the above embodiment, the aeration membrane carrier 3 is mounted above the zoobenthos enclosure by a fixing member, the fixing member is formed by longitudinally connecting galvanized steel pipes, the horizontal direction is fixed with the PPR pipes, the bottom is connected with the zoobenthos enclosure, and the bottom is inserted into the depth of 0.5 m of the bottom of the sediment.

In the above embodiment, the zoobenthos enclosure is made of a watertight polymer material, which is a rectangular structure and the upper and lower surfaces are not sealed.

In the above embodiment, the benthonic animal is one or more of limnodrilus, chironomus larva and snail.

In the above embodiment, at least two groups of aeration membrane carriers 3 are arranged in the vertical direction, and the lowest membrane tows are arranged 5-15cm away from the water sediment.

As shown in fig. 8 and 9, in the embodiment of the present invention, in order to solve the problem that the root deposit of the hollow fiber membranes used as the carrier for the aeration membranes in the prior art is difficult to be removed, the coupling system of the present invention further provides an improved aeration system including an aeration pipe 8 for mounting the hollow fiber membrane bundles 9 and for aeration, the aeration pipe 8 including a mounting portion 10 for mounting the hollow fiber membrane bundles 9, an aeration chamber 11 formed after mounting the hollow fiber membrane bundles 9, and a gas passage capable of receiving a gas and releasing the gas to the root of the hollow fiber membrane bundles 9, wherein the aeration chamber 11 communicates with the inner cavity of the mounted hollow fiber bundles, and the gas passage and the aeration chamber 11 are disposed in such a manner as not to communicate with each other.

In the embodiment of the present invention, as shown in fig. 8, the bottom of the aeration tube 8 has an approximately circular structure, and its inner cavity is divided into a main gas passage 13 of a gas channel and the aforementioned aeration chamber 11 in the radial direction by an inner partition 12 extending along the length of the aeration tube 8. As shown in fig. 10 and 11, an adjusting plate 14 having an L-shaped overall structure is provided at the intake port of the aeration tube 8 in correspondence with the aforementioned internal partition plate 12, and the adjusting plate 14 is rotatably provided at the intake port of the aeration tube 8 through a rotation shaft 20, and has a first operation position (initial position) and a second operation position, and the adjusting plate 14 can be pushed to move from the first operation position to the second operation position when the gas pressure exceeds a certain threshold value. In the first working position, the first plate body 15 of the adjusting plate 14 is in abutting fit with the inner partition plate 12 and the second plate body 16 of the adjusting plate 14 closes the inlet of the main air passage 13 of the gas channel, at this time the inlet of the aeration chamber 11 is opened, and the gas from the gas generating device can only enter the aeration chamber 11 through the inlet port of the aeration tube 8; when the adjusting plate 14 is in the second operating position, the second plate body 16 of the adjusting plate 14 is in abutment with the inner partition 12 and the first plate body 15 of the adjusting plate 14 closes the inlet of the aeration chamber 11, at which time the inlet of the main gas channel 13 of the gas channel is open, and gas from the gas generating device can only enter the main gas channel 13 of the gas channel via the inlet port of the aeration tube 8. The arrows shown in fig. 10 and 11 are the direction of gas conduction.

When the L-shaped adjusting plate 14 is in the first working position, the aeration tubes 8 can only be used for aeration, so that gas enters the hollow lumens of the hollow fiber membrane bundles 9, which in turn supply oxygen necessary for microbial membranes and adjust the dissolved oxygen concentration in the water matrix. When the L-shaped adjusting plate 14 is arranged at the second working position, the aeration pipe 8 can only be used for blowing air to the root part of the hollow fiber membrane bundle 9 exposed outside the mounting part 10 of the aeration pipe 8, so that the shaking of the root part of the hollow fiber membrane bundle 9 is enhanced, the common phenomena that root membrane wires are too dense and easy to accumulate mud due to the pursuing of high filling density of the traditional hollow fiber membrane assembly can be well avoided, the effective filtering area and the filtering uniformity of the hollow fiber membrane wires in the water treatment process can be always maintained, and the service life of the whole bundle of membrane wires can be effectively prevented from being shortened due to the rapid development and spreading of membrane root membrane pollution of the membrane wires.

In the above embodiment, the adjustment plate 14 is positioned at the entrance of the main air passage by the torsion spring 17 in the initial state, and keeps the entrance of the main air passage closed by the torsion spring 17. When the gas pressure from the gas generating means exceeds a set threshold value, the regulating plate is caused to rotate against the torsion force of the torsion spring 17 until it is rotated to the second operating position. Also, in the present invention, the surfaces of the first plate body 15 and the second plate body 16 of the regulating plate are each provided with inclined surfaces 18 and 19, so that in the first operating position of the regulating plate, the surfaces of the first plate body 15 and the second plate body 16 each form a guide surface for guiding the gas to the aeration chamber, while in the second operating position of the regulating plate, the gas can be guided to the main gas duct.

In the embodiment of the present invention, the gas passage further includes a side gas passage 21 provided along the side wall of the aeration tube 8 and gas outlet passages 22 communicating with the side gas passage 21, each gas outlet passage 22 being provided obliquely in such a manner as to enable the release of gas toward the root of the hollow fiber membrane bundle 9.

In the embodiment of the invention, the gas channel for blowing the root of the hollow fiber membrane bundle 9 is integrally arranged on the aeration pipe 8, so that an additional gas distribution device is not required; and by switching operation of the adjusting plate 14, the aeration pipe 8 can meet the two independent works of aeration and purging of the root of the hollow fiber membrane bundle 9.

In addition, in the embodiment of the invention, the mounting part 10 for the hollow fiber membrane bundle 9 provides a mounting cavity 23 which is wavy along the length direction of the aerator pipe 8, the mounting cavity 23 is provided with wave crests and wave troughs, and the hollow fiber membrane bundle is mounted in the mounting cavity by casting or glue sealing, so that the wavy hollow fiber membrane group which is matched with the shape of the mounting cavity 23 is formed after the hollow fiber membrane bundle 9 is mounted on the mounting part 10, and the effective area of hollow fiber membrane wire filtration and the filtration uniformity are greatly improved in the limited length of the mounting part 10. Wherein, the gas outlet channel 22 of the gas channel is respectively provided with at least one corresponding to each wave crest and wave trough of the installation cavity 23 so as to ensure the thoroughness and uniformity of cleaning the root pollution of the hollow fiber membrane bundle 9.

In another embodiment of the present invention, an adjustment mechanism is provided that is structurally different from the aforementioned adjustment plate 14. The regulating mechanism comprises a shell 24, an air inlet 25 and two air outlet passages, wherein the air inlet 25 is communicated with the gas generating device and is used for receiving gas from the gas generating device; the two gas outlet passages are a first gas outlet passage 26 and a second gas outlet passage 27, wherein the first gas outlet passage 26 is used for communicating with the inlet of the aeration cavity 11 of the aeration tube 8, and the second gas outlet passage 27 is used for communicating with the main air passage 13 of the gas channel of the aeration tube 8. The adjustment mechanism includes an airway switching mechanism disposed within the housing 24 that includes an inner housing 28, a diaphragm 39, a first shut-off valve, and a second shut-off valve. Wherein the diaphragm 39 is made of soft material, preferably silica gel, and the diaphragm 39 has a hemispherical structure and can deform in the opposite direction of the initial state under pressure; a diaphragm 39 is disposed within the interior cavity of the inner housing 28 and separates the interior cavity of the inner housing 28 into a first chamber 29 and a second chamber 30.

In the adjustment mechanism of the above embodiment, the first shut-off valve includes the first spring 31, the first push plate 32, the first slide rod 33, and the first shut-off valve body 34, the first slide rod 33 is penetrated outwardly from the first chamber 29 of the inner housing 28, the first spring 31 is provided on the first slide rod 33 inside and outside the first chamber 29 of the inner housing 28, and the first push plate 32 is fixed on the rod end of the first slide rod 33 located in the first chamber 29. The first shut-off valve body 34 is fixedly provided on a rod end of the first slide bar 33 located outside the inner case 28, and can be used to open and close the first outlet passage 26. The second stop valve comprises a second spring 35, a second push plate 36, a second slide bar 37 and a second stop valve body 38, wherein the second slide bar 37 penetrates out from the second cavity 30 of the inner shell 28, the second spring 35 is arranged on the second slide bar 37 in a sleeved mode in the second cavity 30 of the inner shell 28, and the second push plate 36 is fixed on the bar end of the second slide bar 37 located in the second cavity 30. A second shut-off valve body 38 is fixedly provided on a rod end of the second slide bar 37 located outside the inner casing 28, and can be used to open and close the second outlet passage 27.

In the adjustment mechanism of the above embodiment, the diaphragm 39 has the first operating position (initial position) at which the diaphragm 39 is in the initial state, which is the semicircular convex state toward the second shut-off valve, and the diaphragm 39 is in contact with the second push plate 36 of the second shut-off valve, and the second push plate 36 is pressed by the elastic deformation force of the diaphragm 39 itself, so that the second spring 35 is compressed, the second slide rod 37 is stretched to the outside of the inner case 28, and finally the second shut-off valve body 38 of the second shut-off valve closes the second air outlet passage 27. In the first operating position of diaphragm 39, second outlet passage 27 is closed, and at this time, the gas entering from inlet 25 of the self-regulating mechanism can only flow out from first outlet passage 26, i.e. at this time, the aeration operation of aeration tube 8 is enabled. In the second working position of the diaphragm 39, the diaphragm 39 abuts against the second push plate 36 of the first stop valve, and presses the first push plate 32 by virtue of the elastic deformation force of the diaphragm 39 itself, so that the first spring 31 is compressed, the first slide rod 33 extends to the outside of the inner casing 28, and finally the first stop valve body 34 of the first stop valve closes the first air outlet passage 26. In the second working position of the diaphragm 39, the first air outlet passage 26 is closed, and at this time, the air entering from the air inlet 25 of the self-adjusting mechanism can only flow out from the second air outlet passage 27, i.e., at this time, the air blowing work of the aeration tube 8 against the root of the hollow fiber membrane bundle 9 can be performed.

The switching of the diaphragm 39 from the first operating position to the second operating position is effected by means of the air pressure of compressed air. When the blowing operation for the root of the hollow fiber membrane bundle 9 is required, compressed air is filled into the second chamber 30 through the compressed air inlet pipe 40 communicated with the second chamber 30 of the inner shell 28, and when the air pressure in the second chamber 30 reaches a certain threshold value (20-50 KPa), the diaphragm 39 is forced to bend in the opposite direction, namely, a semicircular convex state towards the first stop valve is formed. When it is necessary to stop the blowing operation for the root of the hollow fiber membrane bundle 9, the supply of the compressed air into the second chamber 30 may be cut off, the diaphragm 39 may be restored to the original state, i.e., to the semicircular convex state toward the second shut-off valve, under the restoring force of the first spring 31 of the first shut-off valve, and at this time the diaphragm 39 may force the second shut-off valve to operate so that the second shut-off valve body 38 closes the second air outlet passage 27. In the present invention, the spring force of the first spring 31 of the first shut-off valve is different from the spring force of the second spring 35 of the second shut-off valve, and the spring force of the first spring 31 of the first shut-off valve can force the diaphragm 39 to return to the original state after the supply of the compressed air to the second chamber 30 is interrupted, whereas the spring force of the second spring 35 of the second shut-off valve cannot force the diaphragm 39 to be completely deformed in the direction toward the first shut-off valve. The first chamber of the inner housing has a vent 41 in communication with the interior cavity of the housing to equalize the air pressure between the first chamber and the housing.

The invention also discloses a method for in-situ elimination of the endogenous pollution of the water body, which comprises the following steps:

In the above method embodiments, the oxygen supply to the biofilm through the aerated film carrier further comprises oxygen dissolved at the water substrate-water interface.

Experimental procedure

Indoor culture experiments were employed.

50L of water sample and 20L of sediment are collected. Collecting surface sediment (0-10 cm) from the sediment, filtering coarse particles and large benthonic animals from the surface sediment by using a 100-mesh (0.15 mm) screen, removing upper water by precipitation, uniformly mixing, freezing for 72 hours at a low temperature (-80 ℃), freezing to death of insect eggs and small organisms in the sediment, and thawing and then placing into a device. And taking 100g of treated sediment to measure various indexes (such as water content, porosity, total nitrogen, total phosphorus and the like) so as to obtain an initial sediment background value. Filtering the water sample by using a 500-mesh plankton net, preserving, taking 100mL of filtered water sample, and measuring water quality index (NH) ₄ ⁺ 、NO ₃ ^- 、NO ₂ ^- 、TN、TOC、PO ₄ ^3- TP), the initial water sample background value is obtained. Benthonic animals are obtained from sediment collected from a clean water stream river channel, are cultured in a small amount of non-screened sediment, and are selected and domesticated in a laboratory.

The biological film medium adopts two aeration films, and the aeration film A and the aeration film B are respectively made of PP and PTFE materials. A total of 80 plastic hoses with the length of 8cm and the diameter of 4mm are cut off. 20 PP membrane wires with the length of 17cm are stuck in each plastic hose, and 40 PP membrane wires are manufactured; 10 PTFE membrane wires with the length of 17cm are stuck in each plastic hose, and 40 plastic hoses are manufactured. The membrane filaments of the same material are provided with the shunts, ten shunts are arranged, and 8 shunts are provided with the membrane filaments, and oxygen is blown into the tube through the shunts and then reaches the filaments.

The self-made simulation lake system mainly comprises a water tank, an aeration pump and a flowmeter. The water tank was a rectangular parallelepiped plastic device with length x width x height=18 cm x 16cm x 16.5cm, with an open top. And mixing the stable sediment uniformly, adding 750g of sediment into each water tank, adding 0.2L of filtered water sample to flush the residual mud sample on the wall, and adding 2.3L of filtered water sample into each water tank. Setting up the prepared membrane wire device into a water tank, standing for 1-2 days after the device is set up, clarifying water covered in the water tank, starting an aeration pump, adjusting a flowmeter, and starting an experiment.

When the culture system is stable, benthonic animals, namely limnodrilus are selected, individuals with basically consistent length and size are selected, and added into 750g of evenly mixed sediment for culture, and the biomass is 100 in a water tank of a formal experiment of each system.

Six experimental groups are respectively a blank experimental group (C group), a limnodrilus experimental group (T group) and an aeration membrane PTFE experimental group (M group) _A Group), limnodrilus + aeration membrane PTFE test group (TM) _A Group) aeration membrane PP test group (M _B Group), limnodrilus + aerated film PP test group (TM) _B A group). Each experimental group is provided with two repeated experiments to ensure the accuracy of the experiments. 750g of black and odorous substrate sludge and 2.5L of overlying water are added to each experimental device. Aeration is carried out on groups except the group C and the group T according to the screened preferred aeration quantity. Before animals are added, the water coating of each device is collected, and the water quality index is measured and used as a background value.

And testing the temperature and the dissolved oxygen of the overlying water by using a portable multiparameter water quality tester.

And collecting the overlying water from the system every four days for water quality index measurement. After 50mL of the coating water was sucked from each device by a syringe and filtered by a 0.45 μm water-based needle filter, the dissolved inorganic Nitrogen (NH) was measured by a UV2355 type ultraviolet-visible spectrophotometer ₄ ⁺ 、NO ₃ ^- 、NO ₂ ^- ) And Phosphate (PO) ₄ ^3- ). The water quality index measuring method comprises the following steps: NH (NH) ₄ ⁺ Colorimetric method using Nashi reagent and NO ₃ ^- By ultraviolet spectrophotometry, NO ₂ ^- By N- (1-naphthyl) -ethylenediamine photometry and PO ₄ ^3- -determination by molybdenum antimony anti-spectrophotometry. TP is not filtered, is digested by adopting a potassium persulfate digestion method, and is colorized according to a molybdenum-antimony spectrophotometry. The water sample was filtered through a 0.22 μm glass fiber membrane, and then the total organic carbon content and TN content were measured by high temperature burning using a TOC analyzer (TOC-L CPH, shimadzu, japan).

Experimental analysis results: control effect of benthos-membrane aeration biological membrane coupling system on carbon, nitrogen and phosphorus in water

Law of change of Dissolved Oxygen (DO) in black and odorous system

Fig. 2A depicts the change in dissolved oxygen in the overlying water over time. The DO concentration in the water overlying groups C and T is almost the same, but the dissolved oxygen concentration in group C is slightly higher than that in group T, which is probably the consumption of dissolved oxygen by limnodrilus, M _A 、M _B 、TM _A 、TM _B The group showed an overall rising trend in dissolved oxygen concentration, and finally fluctuated slightly at 3.5 mg/L.

FIG. 2B depicts the depth of oxygen dissolution erosion of the deposit at the end of the experiment, with the depth of oxygen dissolution erosion of group C being very low, about 200 μm, and the depth of erosion of group T being 1000 μm, M _A 、M _B The depth of attack of dissolved oxygen in the group was 900. Mu.m, TM _A 、TM _B The dissolved oxygen attack depths of the groups were 1100, 1400 μm, TM _B The group had the greatest depth of dissolved oxygen attack. The order of magnitude of the dissolved oxygen concentration at the sediment-water interface is M _B ＞M _A ＞TM _B ＞TM _A ＞C＞T，M _B The maximum concentration of dissolved oxygen at the sediment-water interface is about 2.5mg/L for group T and the minimum concentration of dissolved oxygen is about 0.8mg/L for group T, with large differences in dissolved oxygen concentration for each treatment group.

Law of change of organic carbon (TOC) content in overlying water

The TOC concentration in the overlying water over time is shown in figure 3. C. The TOC concentration of the T group was continuously fluctuating, even at the end of the experiment was higher than at the beginning, whereas the TOC concentrations of the experimental groups eventually decreased and did not differ far from each other. At the end of the experiment, the TOC concentrations were in the order C > T > TM _B ＞M _B ＞TM _A ＞M _A The TOC concentration of the group with limnodrilus disturbance and aeration membrane in-situ pollutant elimination is higher than that of the group with aeration membrane only for aeration, which is probably the result of the release of C element in the sediment by limnodrilus disturbance.

Law of variation of N concentration (NH) in different forms in overlying water ₄ ⁺ ，NO ₂ ^- ，NO ₃ ^- ，TN)

Ammonia nitrogen is a reduced form of nitrogen, and the concentration change of ammonia nitrogen in the whole system is greatly influenced by the release rate of ammonia nitrogen and different dissolved oxygen concentration levels caused by different disturbance degrees of water bodies.

As can be seen from FIG. 4, NH in the water over-coating of groups C and T ₄ ⁺ The change of N concentration shows a similar change rule, but the T group NH ₄ ⁺ The perturbation of the N concentration slightly higher than group C, possibly limnodrilus, causes the endogenous contaminants in the deposit to be released. M is M _A Group, M _B Group (TM) _A Group sum TM _B NH of group ₄ ⁺ The change of the N concentration is expressed as three stages of fluctuation, decline and stabilization, the fluctuation is small up and down at 8mg/L for 12 days before the experiment starts, the fluctuation is rapid after 12 days, the stabilization is about 0.3mg/L after 24 days, and the ammonia nitrogen removal rates of each group are 93.3%, 92.5%, 95.1% and 94.0% respectively. M of PP film material _B 、TM _B M of PTFE as the group ratio membrane material _A 、TM _A The concentration of ammonia nitrogen in the group is higher, the surface area of the PP material film is larger, and more microorganism adhesion can be supplied.

FIG. 5 further illustrates NH based ₄ ⁺ N conversion kinetics of one of them from NO ₂ ^- To NO ₃ ^- Is a transition of (2). TM (TM) _A 、TM _B NO in group treatment ₂ ^- Increase in N concentration (2.5 mg/L) with NH ₄ ⁺ The decrease in N corresponds to the subsequent occurrence of NO ₃ ^- New peak value of N concentration (2 mg/L) and NO ₂ ^- The decay peaks of N are substantially uniform. M is M _A 、M _B Similar results were also observed for the other treatments and therefore are not described in further detail. NO of group C ₂ ^- N concentration was fluctuating at 1mg/L up and down 25 days before, throughout the experiment, NO in group T ₂ ^- The concentration of N is about 0.2mg/L, the highest value is 0.42mg/L, and NO ₃ ^- The concentration of N is about 1mg/L and the NO thereof ₂ ^- -N and NO ₃ ^- Minimal change in N concentration. Final NO for each treatment group ₂ ^- The N concentration is almost close to 0, almost complete conversion.

As can be seen from FIG. 6, the last TN of group C, T is reduced, while M _A 、M _B 、TM _A And TM _B The TN concentration of the group shows three stages of fluctuation, decline and stabilization, the concentration fluctuates slightly in the first 12 days, the concentration begins to decline rapidly after the 12 th day, the concentration drops to about 1mg/L in the 24 th day, the concentration change is small after the 24 th day, and the concentration is gradually stabilized, which is similar to NH ₄ ⁺ -a consistent change in N concentration. The total nitrogen removal rate of each experimental group is 87.7%, 89.7%, 84.9% and 83.3%, and the treatment effect is ideal.

Law of variation of phosphorus in overlying water (PO) ₄ ^3- 、TP)

FIG. 7 depicts the phosphorus concentration (PO) in the overlying water for each treatment group ₄ ^3- TP) over time. Initial PO for each treatment group ₄ ^3- The concentration is about 10 mg/L. Po in overlying water ₄ ^3- The concentration is in the order of T group > C group > TM _A Group > TM _B Group > M _A Group > M _B A group. PO of group C and T ₄ ^3- Always shows higher concentration, and reaches 17.51 mg/L and 17.01mg/L at the highest. M is M _A 、M _B 、TM _A 、TM _B Group PO ₄ ^3- The overall concentration showed a decreasing trend, final PO ₄ ^3- The concentration is about 1mg/L, PO thereof ₄ ^3- The removal rates were 89.5%, 92.6%, 84.7%, 95.0%, respectively, but TM _A 、TM _B Group PO ₄ ^3- Concentration ratio M _A 、M _B The group is higher.

TP concentration variation and PO for each treatment group ₄ ^3- The concentration change is similar, and the size sequence of TP concentration in the overlying water is T group > C group > TM _A Group > TM _B Group > M _A Group > M _B A group. The TP concentration of group T was slightly higher than that of group C, probably because the perturbation of the benthonic animals accelerated the release of phosphorus in the sediment into the overlying water. M is M _A 、M _B 、TM _A 、TM _B The overall group TP concentration also showed a decrease, the final TP concentration was about 1mg/L, and the TP removal rates were 90.9%, 90.6%, 85.9%, 93.6%, respectively, but TM _A 、TM _B Group TP concentration ratio M _A 、M _B The group is higher. Wherein the material is PPThe membrane of (2) has better treatment effect on phosphorus than PTFE membrane, and can be made of PP material membrane with smaller diameter and larger specific surface area, which is beneficial to the adhesion growth of microorganism.

Endogenous ecological release under disturbance of benthic organisms (limnodrilus)

Limnodrilus is a typical benthic invertebrate and has very high tolerance to eutrophic, contaminant-rich and low-dissolved oxygen water, often found in severely contaminated water, and has a high viability. At present, related researches show that the limnodrilus has stronger biological disturbance effect compared with other benthonic animals. The biological disturbance of the limnodrilus not only can directly influence the physicochemical properties of the sediment-water interface, such as sediment granularity, dissolved oxygen concentration and Nitrogen (NH) of various forms ₄ ⁺ -N、NO ₃ ^- -N、NO ₂ ^- N), phosphorus content, etc., and may also indirectly affect the exchange and conversion of interfacial species, etc., by affecting the environmental conditions of the sediment-water interface and the number and activity of interfacial microorganisms.

In-water NH for T group ₄ ⁺ N, TN and PO ₄ ^3- The difference in concentration of nitrogen and phosphorus in the overlying water demonstrated that biological perturbation of limnodrilus caused release of nitrogen in the sediment into the overlying water, with TP concentrations higher than those of control group C (fig. 4, 6, 7). The biological disturbance of the limnodrilus can greatly improve the mineralization activity of microorganisms in the sediment, and improve the regeneration efficiency of nutrients, especially the regeneration of phosphorus. The phosphorus dissolved out of the sediment is finally released into the overlying water by bio-diffusion and bio-advection mixing.

In addition, the presence of limnodrilus accelerates oxygen consumption and reduces dissolved oxygen content, which may be beneficial for the growth of anammox bacteria, which is well demonstrated by the doubling of the number of anammox bacteria in group T compared to group C. TM (TM) _A Denitrifying bacteria of group are M _A Double the group, this suggests that biological perturbation of limnodrilus might promote denitrification reactions, by digging holes, limnodrilus not only increases the mud-water interface area and consumption of dissolved oxygen in the sediment, but also intermittently pumps overburden water into these tunnels. It is because of these The life activities, electron acceptors such as nitrate in the overlying water are brought into the lower layer of the sediment, thereby shortening the diffusion distance of nitrate in the overlying water to the anoxic denitrification zone at the bottom layer of the sediment. Meanwhile, bacteria with a larger quantity than the surface layer of the sediment exist in the tunnels, and the bacteria contain a large quantity of denitrifying bacteria to better promote the denitrification reaction of the system, so that the biological disturbance effect has a certain promotion effect on the denitrification reaction.

In view of the best performance of limnodrilus, engineered biological contaminant transfer may help to continue to effectively reduce the pollution load without damaging the sediment microenvironment. Given that biological perturbation of benthonic animals enhances the ability to extract nutrients from contaminated sediment, on-site pollution control of overlying water should be well-suited in combination with other in-situ abatement techniques.

Biological enhancement of membrane-aerated biological membranes

The aeration membrane supplies oxygen to the bioreactor through the aeration device, and in fact supplies oxygen required for metabolism of the biofilm attached to the membrane surface. By aerating the permeable membrane, the DO concentration of the system is increased. The increase in DO promotes NH release of sediment up to the overburden ₄ ⁺ -N-direction NO ₂ ^- -N，NO ₃ ^- Conversion of N, NH of aerated film group ₄ ⁺ The N concentration is reduced from about 8.6mg/L to about 0.15mg/L (FIG. 4), which expands the concentration difference between the overlying water and the ammonia nitrogen in the sediment to a certain extent, and accelerates NH by concentration gradient ₄ ⁺ Release of N, such that NH ₄ ⁺ N is reduced by the use of.

The aeration membrane provides a place for microorganisms to attach to in addition to providing oxygen to the system. The microorganisms form a layered structure according to different oxygen concentration gradients, and the layered structure sequentially comprises the following components from the film to the outside: the aerobic zone, the anoxic zone and the anaerobic zone are provided with different microorganism functional groups in different zones. After the sewage passes through the biomembrane layered structure in the reactor, synchronous Nitrification and Denitrification (SND) can be performed, so that NH ₄ ⁺ Conversion of N to NO ₂ ^- -N、NO ₃ ^- after-NThe nitrogen is discharged after the conversion, ammonia nitrogen is removed mainly by nitrifying bacteria, and the removal of the ammonia nitrogen is enhanced by the rising of DO (figure 2). The inner side of the biological film contacts with the film wire, the oxygen diffusion distance is short, so the oxygen concentration is high, the concentration of the organic matters on the inner side is lower, and then the high-oxygen low-carbon environment is formed, so the interference of aerobic heterotrophic bacteria to functional bacteria is avoided, nitrifying bacteria are easy to grow and propagate in the biological film, particularly nitrifying bacteria growing on the inner side and close to an oxygen source can obtain more sufficient oxygen for nitrifying reaction, ammonia nitrogen is converted and removed, and the ammonia nitrogen removal rate of an aeration film group is higher (figure 4, M) _A 、M _B The ammonia nitrogen removal rates of the groups are 93.3 percent and 92.5 percent respectively.

The aeration film promotes the denitrification process of the sediment, so that the denitrification bacteria amount of the aeration film group is increased, which is probably due to more sufficient carbon source and NO ₂ ^- 、NO ₃ ^- The substrate promotes the effect of coupling nitrification and denitrification (the highest peak of nitrite nitrogen concentration in the water covered on the PTFE membrane group is 2mg/L, the highest peak of nitrate nitrogen concentration is 2.06mg/L, the highest peak of nitrite nitrogen concentration in the water covered on the PP membrane group is 1.05mg/L, and the highest peak of nitrate nitrogen concentration is 3.09 mg/L), so that nitrogen elements are better removed.

The biomembrane attached to the membrane can absorb phosphorus in a dissolved state and adsorb phosphorus in a granular state, so that the concentration of phosphorus elements in overlying water is reduced, and in addition, an isolation layer is formed on the surface of the membrane, so that the release of endogenous phosphorus into a water body is reduced, and in addition, the growth and propagation conditions of the biomembrane can be directly influenced by the phosphorus level in the water body.

In addition, the aeration membrane with larger specific surface area has more obvious effect on black and odorous water bodies, and the membrane made of PP material has more obvious effect on NH ₄ ⁺ N, TN and PO ₄ ^3- The treatment effect of TP is better than that of PTFE membrane (FIGS. 4, 6 and 7), which is the reason that the specific surface area of PP membrane is larger and the adhesion and growth of microorganism are facilitated.

Effect of coupling technique on black and odorous system

Although membrane aerated biofilm and benthonic animals (limnodrilus) each have positive improvements in the black and odorous system, there are limitations to which coupling can overcome.

For the T group alone, the activity of limnodrilus resulted in lower DO in both water and mud, further degrading the micro-habitat of the interface. While in the presence of the aerated film the DO environment at the deposit interface was significantly improved (fig. 2). Another problem with limnodrilus alone is that the quality of the overburden water is poor, group T has higher ammonia nitrogen and phosphorus concentrations, and TM _A The group has good control over the concentration of N and P in the overlying water (fig. 6, 7).

M alone _A 、M _B For groups, aeration membranes promote dissolved oxygen in the mud, while TM _A 、TM _B The group oxygen can be better transferred into the sediment, which is mainly beneficial to the interface gallery opened by the limnodrilus. Although TM _A 、TM _B Group dissolved oxygen and M _A 、M _B The groups are similar, but the results can be attributed to the rapid utilization of DO by microorganisms in the incoming sediment. M is M _A Another problem with the group is that the biofilm on the membrane is difficult to act on the nitrogen and phosphorus in the substrate sludge, while in TM _A In the group, as the pollutants released by the limnodrilus disturbance sediment can be captured in situ by the biological film on the film, so that TN and TP in the sediment are obviously reduced by being converted and removed by microorganisms.

For the coupling technique TM _A 、TM _B The DO levels of the overlying water and sediment-water interfaces of the groups were significantly increased compared to those of group C (FIG. 2, TM at the end of the experiment _A 、TM _B DO concentration in the water of the upper group is 3.15mg/L and 3.8mg/L higher than that of the lower group C, and mud water interface is about 2 mg/L. Compared with the T group, TM _A The water quality condition of the overlying water is better controlled. On day 20 of the experiment, the ammonia nitrogen concentration of the water on the TA and TB groups had fallen to a level below 1mg/L, while the T group was still at a higher concentration level of 9.56mg/L (FIG. 4). Compared with M _A Group (TM) _A The higher penetration depth of dissolved oxygen (fig. 2B), indicating that the presence of limnodrilus promotes oxygen penetration into the interior of the deposit, and the activity of limnodrilus creates more hole galleries.

TM _A Water-over-coating neutralization of sediment in groupThe improvement of DO content of the water interface means that the coupling technology improves the dissolved oxygen environment of the benthonic water body, on one hand, the overlying water is well controlled, the N released by benthonic animal disturbance is solved, on the other hand, the removal of the sediment per se to the N is enhanced, and the self-cleaning denitrification capability is realized.

Finally, it is noted that the above embodiments are only for illustrating the technical solution of the present invention and not for limiting the same, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the technical solution of the present invention, which is intended to be covered by the scope of the claims of the present invention.

Claims

1. The aeration system for in-situ ecological elimination of endogenous pollution of a water body is characterized by comprising an aeration pipe used for installing a hollow fiber membrane unit and used for aeration, wherein the aeration pipe comprises an installation part used for installing the hollow fiber membrane unit, an aeration cavity formed after installing the hollow fiber membrane unit and a gas channel capable of receiving gas and releasing gas to the root of the hollow fiber membrane unit, the aeration cavity is communicated with the inner cavity of the installed hollow fiber membrane unit, the gas channel and the aeration cavity are arranged in a mutually non-communicated mode, and the gas channel and the aeration cavity work in a switchable mode.

2. The aeration system for in-situ ecological elimination of endogenous pollution of a water body according to claim 1, wherein the inner cavity of the aeration tube is partitioned into the main air passage of the gas passage and the aeration chamber in the radial direction by an inner partition extending in the length direction of the aeration tube; an adjusting plate with an L-shaped integral structure is arranged at the air inlet of the aeration pipe corresponding to the inner partition plate, the adjusting plate is rotatably arranged at the air inlet of the aeration pipe and is provided with a first working position and a second working position, and the adjusting plate can be pushed to move from the first working position to the second working position when the gas pressure exceeds a certain threshold value; at the first working position, the first plate body of the adjusting plate is in abutting fit with the inner partition plate, the second plate body of the adjusting plate seals the inlet of the main air passage of the gas channel, at the moment, the inlet of the aeration chamber is opened, and gas from the gas generating device can only enter the aeration chamber through the inlet port of the aeration pipe; when the adjusting plate is at the second working position, the second plate body of the adjusting plate is in abutting fit with the inner partition plate, the first plate body of the adjusting plate seals the inlet of the aeration chamber, at the moment, the inlet of the main air passage of the gas passage is opened, and gas from the gas generating device can only enter the main air passage of the gas passage through the inlet port of the aeration pipe.

3. The aeration system for in-situ ecological elimination of endogenous pollution of a body of water according to claim 1, further comprising an adjustment mechanism comprising a housing, an air inlet, a first air outlet channel for communicating with an inlet of an aeration chamber of the aeration tube, and a second air outlet channel for communicating with a main air channel of a gas channel of the aeration tube;

the regulating mechanism further comprises an air passage switching mechanism arranged in the shell, the air passage switching mechanism comprises an inner shell, a diaphragm, a first stop valve and a second stop valve, wherein the diaphragm is provided with a first working position and a second working position, the diaphragm is in an initial state and is in a semicircular protruding state towards the second stop valve, in the initial state, the diaphragm is in contact with a second push plate of the second stop valve, the second push plate is pressed by virtue of elastic deformation force of the diaphragm, a second spring of the second stop valve is compressed, a second slide rod of the second stop valve extends to the outside of the inner shell, and finally a second stop valve body of the second stop valve closes a second air outlet passage; at the second working position of the diaphragm, the diaphragm is abutted against the first push plate of the first stop valve, and the first push plate is pressed by means of elastic deformation force of the diaphragm, so that the first spring of the first stop valve is compressed, the first sliding rod of the first stop valve extends to the outside of the inner shell, and finally the first stop valve body of the first stop valve closes the first air outlet channel.

4. An aeration system for in situ ecological elimination of endogenous pollution of a body of water according to claim 3, wherein the transformation of the diaphragm from the first operating position to the second operating position is carried out by means of the air pressure of the compressed air.

5. The aeration system for in-situ ecological elimination of endogenous pollution of a water body according to claim 3, wherein the first slide bar of the first stop valve penetrates out from the first cavity of the inner shell, the first spring is sleeved on the first slide bar inside and outside the first cavity of the inner shell, the first push plate is fixed on the rod end of the first slide bar positioned in the first cavity, and the first stop valve body is fixedly arranged on the rod end of the first slide bar positioned outside the inner shell for opening and closing the first air outlet channel.

6. The aeration system for in-situ ecological elimination of endogenous pollution of a water body according to claim 3, wherein the second slide bar of the second stop valve penetrates out from the second cavity of the inner shell, the second spring is sleeved on the second slide bar inside and outside the second cavity of the inner shell, the second push plate is fixed on the rod end of the second slide bar positioned in the second cavity, and the second stop valve body is fixedly arranged on the rod end of the second slide bar positioned outside the inner shell for opening and closing the second air outlet channel.

7. The aeration system for in-situ ecological elimination of water body endogenous pollution according to any one of claims 1 to 6, wherein the gas channel further comprises a side gas channel arranged along a side wall of the aeration pipe and a gas outlet channel communicated with the side gas channel, each gas outlet channel being obliquely arranged in such a manner that the gas can be released to the root of the hollow fiber membrane bundle.

8. An aeration system for in-situ ecological elimination of endogenous contamination of a body of water according to claim 7, wherein the mounting portion for the hollow fiber membrane unit provides a mounting cavity that is wavy along the length of the aeration tube, the mounting cavity having peaks and valleys.

9. The aeration system for in-situ ecological elimination of endogenous pollution of water body according to claim 8, wherein at least one air outlet channel of the air channel is arranged corresponding to each wave crest and wave trough of the installation cavity.